\begin{tikzpicture}
    \tkzDefPoints{0/0/O}
    \tkzDefPoint(120:1.5){A}
    \tkzDefPoint(350:1.5){B}
    \tkzDefPoint(240:1.5){C}
    \tkzDefPoint(40:1.5){D}
    \tkzInterLL(A,B)(C,D)  \tkzGetPoint{P}

    \tkzDrawCircle[thick](O,A)
    \tkzDrawPoint(O)
    \tkzDrawSegments(A,B  C,D)
    \tkzDrawSegments[dashed](A,C  B,D)
    \tkzLabelPoints[above](O)
    \tkzLabelPoints[above](A)
    \tkzLabelPoints[right](B)
    \tkzLabelPoints[below](C)
    \tkzLabelPoints[right](D)
    \tkzLabelPoints[below=.3em](P)
\end{tikzpicture}

